Polishing car windscreens - micro scatches

Yeah, I have the same, and was wondering similar (although I was wondering if it was something that could be done professionally, there's no chance I'm having a go myself)

Halfords (and other brands) will do "intensive glass cutter" type products, it's basically T-cut for glass and works reasonably well for getting decades of pock marking and scratches out.

A drill / grinder pad attachment would definitely make the process a bit quicker as it's obviously a lot harder than paint.

Anyone have any recommendations? I will check with insurance – I know we can have it repaired for free/not much if it gets chipped, but don’t think scratches are covered.

Insurance won't pay for wear and tear on the windscreen, only if it's broken by an actual event.

I've tried it - not a massive success but I didn't persevere for all that long

£100 excess on the windscreen bit of the insurance sorted mine out. Replaced and 12yr old windscreen and the difference was amazing! It was actually an accidental break though. Some long bits of wood that I was taking to the tip. Loaded up the night before and they settled during the night in a way that pushed the front of them up and cracked the screen from the inside.

I used Carpro Ceriglass with a rotary polisher to do this, i wouldn't recommend it.

A) even after a long time polishing (1 hr+) , the microscratches* were not improved much in the way i wanted, they still catch the sun at this time of year

B) larger scratches were not improved at all

C) the polish is the worst I've ever used for splattering all over the place

D) the glass gets extremely hot

E) did i mention, it takes forever

* for reference, you can't catch them with a fingernail, you just *just* about detect a slight texture change with the fingertips. I can't be sure but I believe they were caused by the  wipers automatically starting after the car had been parked under a conifer for a few days

I have never seen DIY glass polishing end well*. Either polish splattered everywhere and no noticeable improvement or cracked glass from the heat of over polishing. Not sure if professional cleaners are any better, or that much cheaper than a new screen.

If you do find something that works, let me know as 2 of my cars would benefit.

*Headlights can be massively improved with simply car polish as long as you keep the buffer moving and don't loiter in one area too long.

Here are the before and after photos for the sidelights/indicators. About 20 minutes work.

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What if it were to 'accidentaly' get stone chiped?

For insurance, it needs to be accidently cracked. They won't replace it for screen chips even if it is within the MOT fail area. They also get quite suspicious if they refuse a stone chip claim and you submit a claim for storm damaged* smashed screen a week later.

*hit by a neighbours trampoline. Fortunately I had a photo to prove it.

Insurance won’t pay for wear and tear on the windscreen, only if it’s broken by an actual event.

Definition of actual event ? .

I mean a brick hitting a window in your hand is an actual event.

What is the actual life expectancy of a windscreen? I mean the mileage, before it gets worn by the wipers so you get a haze or blur etc when its wet/dark? 100,000miles?

Glass is far too hard to remove marring. A pointless exercise.

Definition of actual event ? .

I mean a brick hitting a window in your hand is an actual event

I once saw a seagull fly into a windscreen carrying an axe wrapped in a towel. True story

No help to the op now but my approach to windscreen longevity is new wipers each autumn. Best money you'll spend.

What is the actual life expectancy of a windscreen? I mean the mileage, before it gets worn by the wipers so you get a haze or blur etc when its wet/dark? 100,000miles?

How long is a piece of string, I guess.. dirty wiper blades with grity dirt/leafs and twigs on them would have the largest impact over time I guess.

Wipers are for clearing water, not for cleaning the glass, so wouldn't wear the glass in any significant way, I wouldn't think.

So if your windows look like this: hose them down and give the blades a wipe rather than relying on the wipers to clean the dirt, therefore scratching the glass.

once saw a seagull fly into a windscreen carrying an axe wrapped in a towel. True story

Strange I've seen a few of those in my time too.

Definitely just get it replaced on insurance - all you need is for a rock to fall off a pickup in front and crack the screen and pay the excess.

I try to not use the wipers and rely on Rain X. It is surprisingly good for rain, not so good for nasty salty gritty road spray.

not so good for nasty salty gritty road spray.

Thinking about it, winter road spray is probably the largest contributor to windscreen scratches over time...all that muck and rock salt kicked up at 70mph I imagine creates quite a good grinding paste, and you don't have the option of not using your wipers to clear it.

I had deep scratches on my windscreen with no amount of polishing effective.

In the end, I paid £50 (you will pay more now) to get a guy to use the industrial glass polishing to grind / shave off a layer off the windscreen.

It needs to be expertly done or the windscreen will break if the pressure is applied too much during the polishing process and the heat generated from the polishing the windscreen.

When the polisher was at work, he basically shaved off a layer of the windscreen and constantly checking the temperate.  There was plenty of glass/plastic mixed shaved bits and it smelled like burning plastic.

Be prepared for a replacement windscreen in the event that it breaks during the polishing process.  I was prepared for that but just thought I gave the industrial polisher a try.

Also the polisher ensured the polish was even so the whole windscreen was polished./shaved off.

After that all fine and the wind screen is Not weaker.

Don't forget ..... Aftermarket windscreens favoured by your insurance tend to be shite.

I've never had an after market one last more than a couple of years. Yet the original usually lasts 10.

Can't always be that lucky with the original/unlucky with the new one surely......and the new ones always pick up minor scratches/marks easier.

Isn't glass (especially toughened windscreen glass) too tough to polish? Genuine question tbf, as I've never heard of windscreen polishing.

The normal action of polishing as I understand it is to either heat/melt the surface enough to flow the irregularity out if its soft enough, as WCA polishing his side repeaters (which should be a polycarbonate of some kind). Or to remove enough of the surface as to 'lift' the fault from the area,  but this then leaves surface deformation that needs to be blended to look good.

Anything that can remove scratches from tough glass would either heat the glass so much as to discolour it or remove the surface so much the you'll end up looking through the bottom of a pint glass.

I've polished a scratch out of a rear screen using cerium oxide polish. It didn't heat the glass up much but I was doing it by hand.

I wouldn't want to do a windscreen, I care far more about the visual accuracy looking forward.

Isn’t glass (especially toughened windscreen glass) too tough to polish? Genuine question tbf, as I’ve never heard of windscreen polishing.

Yes, I have never heard of them before I tried them. He was basically using a powerful grinder to shave the windscreen.

I was going to replace the windscreen using 2nd hand part but thought I would give that a try.

I don't think it is glass but some sort of a mixed with glass, hence the plastic smell.

The guy was an expert and there was no uneven spot nor did he use any thing to "melt" the windscreen.

My car is just a Toyota Corolla 2005 with no fancy windscreen.  Therefore, nothing fancy that would go wrong except breakage.

I've tried Auto Finesse glass polish. Absolute garbage (like most of their other products to be fair).

After that all fine and the wind screen is Not weaker.

So someone shaved a layer off your car windscreen and its not weaker? OK...

Don’t forget ….. Aftermarket windscreens favoured by your insurance tend to be shite.

I’ve never had an after market one last more than a couple of years. Yet the original usually lasts 10.

Can’t always be that lucky with the original/unlucky with the new one surely……and the new ones always pick up minor scratches/marks easier.

Same here, OH's fiesta got a new screen a couple of years back and it's got a few big scratches already, including one somehow on the inside . It's also a funny color, or maybe it just refracts light differently because I'm sure it sometimes looks blue and other days yellow, it's definitely filtering out some wavelengths.

The heating elements on my old car and the work transit (which seemed to be particularly prone to chips and cracks) were more visible too,

So someone shaved a layer off your car windscreen and its not weaker? OK…

The strength comes from the fact it's laminated over a plastic layer.  Polishing off a few microns won't have a measurable impact.

fettlin

Full Member
Isn’t glass (especially toughened windscreen glass) too tough to polish? Genuine question tbf, as I’ve never heard of windscreen polishing.

The normal action of polishing as I understand it is to either heat/melt the surface enough to flow the irregularity out if its soft enough, as WCA polishing his side repeaters (which should be a polycarbonate of some kind). Or to remove enough of the surface as to ‘lift’ the fault from the area,  but this then leaves surface deformation that needs to be blended to look good.

Anything that can remove scratches from tough glass would either heat the glass so much as to discolour it or remove the surface so much the you’ll end up looking through the bottom of a pint glass.

The very lightest surface damage can be polished out, but it takes a lot of time and the correct polish/pad. Usually rayon pad with a polish with cerium oxide in it. As I mentioned, I used the CarPro Ceriglass kit to do mine, and it restored the 'sparkle' to the screen really nicely but didn't remove even the most minor scratches.

I think any kind of scratching will mostly likely need a much more aggressive sanding, like the first few passes in the video, and as you say, I guess you'd have to blend it out a really long way to avoid distortion on a windscreen.

spoke to insurer (Admiral) and they will replace on the insurance, the excess is £115 so not too bad.

I've tried a few different cleaners to see if it's some sort of surface contamination. The disc brake cleaner made it lovely and clear when it was dry - and no visible scratches - but as soon as it was wet, it was rubbish again. Going to try some rain repellent to see what that does. Maybe its a problem with an old coating or treatment?

@Lodger - insurance are replacing a (10 years worth) scratched windscreen for just the excess?

You didn't have to make an accidental motorway mishap crack in it?

Wow...

Time to call my insurer and demand similar!.....

No. Was pretty easy. I said not chipped or cracked, just rubbish at night.

Autoglass dont have any drop down menus for that, but I rang them up and they booked it in for Monday. Wanted £40 extra for their rain repel coating, bit the bottles of it are only £8ish so thought I'd try that first

Wife insists whatever it is occurred when I borrowed the car to get to a job in Newport.  It did get very dusty (i was working in the port) but I didn't use the wipers and went straight to a car wash and had it pressure washed before they wiped it. Just Newport corrosive environment i guess.

Wipers are for clearing water, not for cleaning the glass, so wouldn’t wear the glass in any significant way, I wouldn’t think.

No, they don’t, but

all that muck and rock salt kicked up at 70mph I imagine creates quite a good grinding paste, and you don’t have the option of not using your wipers to clear it.

is what does the damage - sand, which gets blown onto roads, as well as spread from trucks carrying it, is quartz, and is remarkably effective at scratching glass, which is made from quartz/sand.

Headlight lenses are mostly plastic, which is why they go cloudy and yellow, and they can be polished.

Having seen a remarkable number of car screens with cracks in while working in logistics, I asked an Autoglass fitter who was replacing a screen and re-calibrating the sensors and cameras about modern screens, and he confirmed my suspicions that modern screens are a fair bit thinner than a couple of decades ago, basically to save weight, and to cause less distortion to the sensors mounted on the back, which is why they crack for very little reason sometimes.

A replacement screen for my Ford is around £1000, because it’s heated - I make sure it’s covered under the insurance. A panoramic glass roof, which can be cracked when loading a roof rack or carrier, or even something dropping from a tree, that’s £12-1500. An LED headlight unit? About the same, £12-1500.

Personally, I ignore small marks on my screen, there’s one or two tiny chips, but they’re no more noticeable than the heating element in the glass, usually - very low level sunlight will show them up, but regular applications of RainX are the best thing.

Big tip is to never cheap out on wiper blades, buy branded genuine (nothing from amazon or ebay is reliably not fake). Screenwash all the time not just water.

Clean your screen and blades by hand a few times a month, don't have to be crazy, especially the blade parking area. If your going for a super deep clean, do your regular glass cleaning things, then 'clay it', use fresh chunk of clay obviously, you'll be amazed what chunks of rock and brake iron are sticking out of your screen. Clean and rinse again, dry. Isoprop it and wick the dirt out of the deeper holes and scratchs with cotton buds. Then get some '0000' wire wool, and carefully wire wool entire screen, by 2nd or 3rd pass you should stop feeling the drag of the small bits of brake iron and other items sticking out of the glass. Wash again, then treat with whatever your sealant of choice is. You pretty much won't need wipers to be turned on for about a month because water will bead off its better than when new, anything over 20 mph, waters gone!

Have good washer jets. Had loads of hire cars around UK and Europe recently, and even relatively expensive SUV and faux 4x4 things have really crap washer jets, just 2 or 3 little spray jets, leaving lots of dry screen for the blades to grind the dirt into the glass with. Had various old Saab + Volvo which universally seem to be able to splatter the entire screen instantly before the blades start moving? And thats 30 year old cars, why do new ones not have this? Price or do people not notice these 'old' features are missing on £30-70k price point vehicles?

Polishing laminated glass is a fools game. Only thing you may achieve is cleaning up the tiny various angles of cut within the deeper cuts that get into past the top layer/laminate. I've ran cars from new past 200k on original screens and never really had much 'marring' on them, but I am borderline anal with glass cleaning routine, rest of the cars external surfaces I could give a monkeys about, but glass, makes me feel travel sick if its dirty or greasy when looking through it.

Polishing laminated glass is a fools game. Only thing you may achieve is cleaning up the tiny various angles of cut within the deeper cuts that get into past the top layer/laminate.

I’m pretty sure that modern screens aren’t laminated, I’ve seen far too many cracked screens, even had one cracked by a bolt thrown up by a truck which hit the edge of the screen on the black band; I actually saw the bolt spinning as it came towards me at a closing speed of roughly 150 mph - I was on a dual carriageway doing 70. The glass was cracked right through, I could feel the edge on both sides with my fingernail. I could see the double impact marks of the head and end of the bolt as well.
The bloke at the dealership I’d just dropped the car off at wasn’t best pleased!
Sod all I could do to avoid the bolt, which I told him. Made a hell of a bang, the crack was about 4-5cm long. Could have been worse, but that was a new screen needed before the car got into the showroom.

Regarding polishing a glass screen, there are a few makes that have a coating on the glass to cut down on heat from solar radiation, Renault used to have it, among others. Not a good idea to try polishing that off…

I’m pretty sure that modern screens aren’t laminated, I’ve seen far too many cracked screens...snip

Sorry to be argumentative 🙂 but I think that most cars still use laminated glass for the 'screen and toughened/tempered glass for the rest. Laminated glass will chip and crack, possibly both layers, but the plastic laminate layer (PVB plastic) holds the glass layers together. Modern glass is very thin because of weight

You'll find a marking scheme on modern screens, which varies because there's a minimum (manufacturer and compliance markings). This includes a certifying country code, e.g. E11 is UK, and a code beginning 43R which is the EU standard

Some manufacturers will add more info. Some (my van) will say "Laminated", others (our car) don't
Some have a "/" code:
/ Tempered
// and /// Laminated
V and VI are used for darkened glass (but I don't think that this is used on a 'screen, just the //)

Number and dot date codes, etc.

Glass tech makes polishing a concern because some will be water-repellent, solar-repellent, secure, noise-reducing, etc. I've no idea which of these is a surface coating and what is construction, e.g. laminated glass is better for security, a cooler interior and noise-reduction

Hopefully @mert will weigh-in

Definitely just get it replaced on insurance – all you need is for a rock to fall off a pickup in front and crack the screen and pay the excess.

Maybe find the thread on claiming for a windscreen effecting premiuma etc. Before proceeding

https://singletrackmag.com/forum/topic/replacement-windscreen-hiking-up-insurance-quote-is-this-new/

Plus it’s fraud

Maybe find the thread on claiming for a windscreen effecting premiuma etc. Before proceeding

If windscreen needs replacing it needs replacing....

Given that the OP had their windscreen replaced under insurance two months ago I'm guessing this is a spam-resurrected thread and they no longer need advice?

If windscreen needs replacing it needs replacing….

i can’t argue with that. My suggestion is that the costs and future likely hood of higher premiums be considered

Here’s a slightly cracked screen I took a photo of at work. Pretty sure that wouldn’t pass an MOT…

It shows just how easy modern screens will crack, and why it’s unlikely that it would be laminated, the plastic mid-layer would tend to allow chips, but stop splits or cracks. The white line is just a paint pen used to show that it had been noticed by whoever was doing arrival inspections and it had been recorded. Probably by me.

...the plastic mid-layer would tend to allow chips, but stop splits or cracks.

It reduces the chance of penetration, but that's it. Have a look at the manufacturer's markings on the glass (usually in a bottom corner), which is more likely to be definitive 🙂

The other type of 'screen is a glass-plastics screen, but I doubt that they're so common. Willing to be wrong on that though

im not sure what the photo aboves trying to show .... if that was anything other than a laminated screen it would be in a million bits in the drivers face.

Just seen this!

I’m pretty sure that modern screens aren’t laminated

100% of all windscreens are laminated. Have been for 3 or 4 decades. Only exceptions might be a few limited volume production  or imported vehicles.

Some manufacturers use laminated front side door windows too (cuts down on noise slightly). Most of the rest is toughened/tempered in some way.

and he confirmed my suspicions that modern screens are a fair bit thinner than a couple of decades ago

Also not 100% true. A few manufacturers have gone thinner, others have gone tougher/flatter/higher spec. The windscreen also has a significant impact on crash (frontal/roll over) so i doubt many will keep up with the thinner screens.